If you suspect that the money you pay for medical treatment fuels high medical salaries, you are correct. No less an authority than the U.S. Department of Labor marks doctors as having the best salaries in the United States.

This information is further supported by an annual compensation survey administered by the Association of American Medical Colleges. They represent all 134 accredited U.S. medical schools and 400 teaching hospitals and health systems, which cover 125,000 faculty members, 75,000 medical students and 106,000 resident physicians.

The survey lists the following five specialties as the best paying, ranking from lowest to highest. In comparison, general practitioners earn up to $220,196 annually, and general surgeons get $383,333 per year.

Gastroenterology

Gastroenterologists study a subspecialty of internal medicine that concentrates on the digestive track including the stomach, intestines, colon and esophagus. They may treat conditions such as constipation, ulcers, hemorrhoids and cancer. They do not perform surgery, but may perform biopsies or exam internal organs through endoscopes.

They must complete four years of undergraduate school, four years of medical school, three years of residency in internal medicine. They then continue with an additional two or three years in gastroenterology. They often also study hepatology, which covers the liver, pancreas and biliary tree, which transports bile from the liver to the small intestine. They start off the list of the highest paid doctors with a maximum of $481,923 per year.

Invasive Cardiology

Invasive cardiologists are physicians who not only diagnose and treat conditions of the heart and cardiovascular system. As opposed to non-invasive cardiologists, they perform catherization to locate blocked arteries. This involves inserting a catheter, which is a small tube, through the blood vessels until it reaches the heart. They do not perform surgery, which is the province of cardio-thoracic surgeons.

Training includes four years of college, four years of medical school and three years of residency, followed by two or three years of specialization. They max out at $495,000 per year.

Plastic Surgery

Plastic surgeons reconstruct, repair or replace physical defects in the head and face, musculoskeletal system, skin, and extremities such as hands or breasts. They can effect these repairs to correct congenital problems and accidental trauma, or to improve cosmetic appearance.

Their education encompasses four years of undergraduate school, four years of medical school, and five or seven years of specialty training. They earn up to $499,656 per year.

Radiation Oncology

Radiation oncologists use radiation to manage diseases, primarily those relating to malignant tumors, such as cancers of the brain, breast, lung and prostate. It can be combined with surgery performed by surgical oncologists, or chemotherapy, which is typically controlled by clinical oncologists, who can also handle radiation therapy.

Training for radiation oncologists covers four years of undergraduate study, four years of medical school, one year of general medical training and four years of radiation oncology training. They make up $518,991 per year.

Orthopedic Surgery

Orthopedic surgeons specialize in restoring function to the musculoskeletal system, which includes the spine, hip, knee, shoulder, elbow and extremities. They can use medicine, physical manipulation or surgery to treat medical problems in both adults and children.

Orthopedic surgeons train for four years in undergraduate studies, four years in medical school, one year in general surgery, and four years in orthopedic surgery, with six months devoted to the treatment of children. They are the highest paid doctors, with compensation up to $600,000 per year.